A fourth generation (4G) communication system is under development to offer services of various Quality of Service (QoS) levels to users at a transfer rate of about 100 Mbps. In particular, the 4G communication systems are advancing to support high-speed services by guarantying mobility and QoS in broadband wireless communication systems such as wireless Local Area Network (LAN) systems and wireless Metropolitan Area Network (MAN) systems.
To support the broadband transmission network in the physical channel, the wireless communication system employs Orthogonal Frequency Division Multiplexing (OFDM)/Orthogonal Frequency Division Multiple Access (OFDMA) scheme.
Using the OFDM/OFDMA scheme, the wireless communication system transmits signals by maintaining orthogonality between a plurality of subcarriers and thus features good frequency use efficiency and robustness against the multipath fading. By using the OFDM/OFDMA scheme, the wireless communication system can achieve the optimum transmission efficiency in the high-speed data transmission.
The wireless communication system based on the OFDM/OFDMA scheme needs to calculate RoT or IoT. However, being not able to measure a thermal noise power, the calculation of the RoT or the IoT is infeasible.
In addition, the wireless communication system provides no apparatus and method for determining whether or not the frequency band licensed to a wireless communication provider is illegally used. As a result, the wireless communication system cannot block the illegal use of the frequency band.